Sean O'Brien is set to leave Leinster for London Irish after this year's World Cup.
RTÉ Sport has reported that the move to London Irish will be confirmed next week, with the "Tullow Tank" set to link up with former Ireland head coach Declan Kidney and Les Kiss at the Reading-based club.
The back-row forward will turn 32 next month and was unlikely to see his IRFU central contract renewed on a multi-year basis.
According to Rugbypass.com, O'Brien has been offered a three-year contract worth £450,000 (€514,000) per annum by London Irish, who look set to make a return to the Premiership next season.
The Rugby World Cup kicks off in September.